Foamed Polyolefin Beads Antistatic Covering Layer
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Solution Overview
Problem
Foamed polyolefin resin beads used in packaging and cushioning applications face issues with antistatic performance degradation over time, humidity dependence, contamination of packaging products, and reduced fusion bonding properties due to the use of surfactants and hydrophilic polymers, which also lead to shrinkage and damage to the cell structure during molding.
Innovation Solution
The development of composite resin foamed beads with a core layer of crystalline polyolefin resin and a covering layer of crystalline or noncrystalline polyolefin resin with a lower melting point, where the polymer type antistatic agent is blended with the covering layer, allowing for improved fusion bonding and antistatic performance without the need for high surfactant concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surfactant is used to impart antistatic performance to foamed polyolefin resin beads, then antistatic performance is improved, but the surfactant adsorbs moisture in the air and the antistatic effect cannot be produced under low humidity environment
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating hydrophilic polymer and polymer type antistatic agent into the foamed resin bead matrix, transforming the antistatic mechanism from surface adsorption (humidity-dependent) to bulk conduction (humidity-independent), thereby maintaining antistatic performance across varying humidity conditions
Solution Approach 2:
The patent creates a composite material system by combining polyolefin resin with hydrophilic polymer and polymer type antistatic agent, where the hydrophilic polymer provides water absorption capability and the polymer type antistatic agent provides stable antistatic performance, resulting in a composite that overcomes the limitations of pure surfactant treatment
2Reliability
If surfactant is applied to the surface of molded article to provide antistatic performance, then antistatic effect is achieved, but the surfactant is easily flaked off from the surface and antistatic effect cannot be produced after separation
Solution Approach 1:
The patent extracts the antistatic function from the surface coating (prone to flaking) and integrates it into the bulk material composition, where the polymer type antistatic agent is incorporated within the foamed resin bead structure, ensuring permanent attachment and continuous antistatic effect
Solution Approach 2:
The patent merges the antistatic agent with the structural matrix of the foamed resin bead through incorporation during foam formation, creating a unified material where the antistatic function is an intrinsic property rather than a separate surface layer, thereby preventing flaking and ensuring durability
3Object-generated harmful factors
If hydrophilic polymer is added to prevent surfactant transfer to packaging products, then contamination is reduced, but fusion bonding properties of foamed resin beads are reduced
Solution Approach 1:
The patent optimizes the molecular weight and composition parameters of the hydrophilic polymer to achieve a balance where sufficient water absorption occurs to prevent surfactant transfer, while the polymer structure and concentration are controlled to minimize interference with the fusion bonding mechanism of the polyolefin resin during molding
Solution Approach 2:
The patent develops a composite formulation where hydrophilic polymer, polymer type antistatic agent, and polyolefin resin work synergistically, with the hydrophilic polymer preventing contamination by absorbing excess surfactant and moisture, while the overall composite composition is tuned to maintain adequate fusion bonding properties for molding
4Reliability
If polymer type antistatic agent is added to achieve high antistatic performance, then antistatic effect is improved, but foaming properties are inhibited and fusion bonding properties are reduced
Solution Approach 1:
The patent carefully selects and adjusts the concentration, molecular weight, and chemical structure parameters of the polymer type antistatic agent to achieve high antistatic performance while minimizing its inhibitory effect on foaming expansion and fusion bonding, finding an optimal parameter range where all properties are satisfied
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides foamed polyolefin resin beads with excellent antistatic performance, reduced shrinkage, and enhanced mechanical strength, while maintaining a good surface condition and preventing antistatic agent transfer to packaging products, thus addressing the limitations of existing methods.
Implementation Method 1
the polymer type antistatic agent is blended with the covering layer... providing foamed polyolefin resin beads with excellent antistatic performance
Implementation Method 2
the surfactant present on the surface of the molded article surface adsorbs moisture in the air
Implementation Method 3
when resin particles are heated in an aqueous medium under pressure, resin particles absorb water. When the expansion ratio is high, the pressure in the cells of the obtained foamed resin beads is reduced by water condensation
Data Source
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AI summary
The present invention relates to foamed polyolefin resin beads. Further, the present invention provides foamed resin beads obtained by foaming and expanding composite resin beads which include a core layer constituted by a polyolefin resin and a covering layer which covers the core layer constituted by a polyolefin resin, wherein (a) the polyolefin resin constituting the core layer is a crystalline polyolefin resin, (b) the polyolefin resin constituting the covering layer is a crystalline polyolefin resin which has a lower melting point (B) than a melting point (A) of the polyolefin resin constituting the core layer, wherein a temperature difference [(A)-(B)] between the melting point (B) and the melting point (A) is more than 0°C and 80°C or less, or a noncrystalline polyolefin resin which has a softening point (C) lower than the melting point (A) of the polyolefin resin constituting the core layer, wherein a temperature difference [(A)-(C)] between the softening point (C) and the melting point (A) is more than 0°C and 100°C or less, and 10% by weight or more and less than 50% by weight of polymer type antistatic agent is contained in the covering layer. The foamed polyolefin resin beads of the present invention provide foamed polyolefin resin beads are excellent in fusion properties between beads at the time of molding in a mold, capable of providing a molded foamed article which is excellent antistatic performance, has no deterioration of the antistatic performance with age, whose antistatic performance is not humidity dependent, does not contaminate packaging products, has a good molded foamed article surface, and has excellent mechanical properties.